1. Field of the Invention
The present invention relates to a tool for opening and closing the buckles on ski boots.
2. Description of the Prior Art
A conventional ski boot including a pivotal buckle is shown in a schematic sectional view in FIG. 1. A conventional ski boot typically includes a plurality of buckles, only one being shown in side view in FIG. 1. The ski boot includes an outer shell 10 including an outer half 11 and an instep half 12, instep half being slideable in relation to outer half 11 to provide for adjustment of the tightness of the boot on the foot of the skier. The interior parts of the ski boot such as the bladder and the lining are omitted to simplify the drawing. The instep half 12 of shell 10 includes an anchor 13 extending therefrom which provides for securement of one end of a strap 14. Strap 14 typically has the shape of an elongated loop and is made from twisted wire strands and which is, in part, coated with plastic. Buckle 15 has a generally elongated shape and is pivotal about axis P. The intermediate portion of buckle 15 includes a plurality of teeth 16 defining gaps 17 therebetween. The second end 18 of strap 14 may be releasably positioned within the gaps between the teeth. The tightness of the boot will be determined by the gap in which the second end of strap is positioned. For example, if the end 18 of strap 14 is positioned in the gap a distance of d.sub.1 from the pivot axis P, the boot will be relatively loose because instep half 12 of shell 10 slides a relatively small distance in relation to outer half 11 when the buckle is pivoted clockwise to the closed position. As the distance between the gap in which strap 14 is positioned and the pivot axis P is increased, the tightness of the boot is increased.
During the time a skier is skiing downhill, it is desirable to have the buckles on the ski boots at relatively tight settings. Generally speaking, the tighter the buckles, the less movement between the skier's foot and the skier's boot and the more control the skier will have over the skis. As the ski boot is tightened, pressure is imposed upon the foot of the skier, and the pressure may result in discomfort to the skier. A skier typically tightens his boots just prior to beginning a downhill run. When the skier reaches the bottom of the mountain, the buckles may be loosened to provide for comfort during the ride up the mountain. Thus, during the course of a day, a skier may open and close the buckles on the ski boots on numerous occasions.
Referring to FIG. 1A which is a force diagram for the buckle shown in FIG. 1, as the skier seeks to tighten the buckles further by positioning the end of strap 14 in a gap further away from pivot axis P, the force, F.sub.applied, required to close the buckle increases. The increasing force is due to at least two factors. Firstly, in order to slide instep half 12 with respect to outer half 11 a relatively large distance to tighten the boot, the resistance of movement of the halves with respect to each other is relatively large and must be overcome: as shown in FIG. 1A, the y component of the load force, Fy, increases. Secondly, as the distance between the pivot axis P and the gap in which the end 18 of strap 14 is placed increases, the mechanical advantage or leverage to the skier decreases. For example, referring to FIG. 1A, the movement about axis P in the clockwise direction must exceed the moment in the counterclockwise direction. Thus, the following inequality would apply: EQU F.sub.APPLIED &gt;(Fy d)/1.sub.0
In the above equation, 1.sub.0 is the distance at which the force is applied by the skier. d is one of the distances (d.sub.1, d.sub.2, d.sub.3, d.sub.4 or d.sub.5) at which the y component of the load force, F.sub.y, is applied. Since 1.sub.0 is constant, as the distance, d, between the pivot axis, P, and the gap in which the strap is positioned increases, the force applied to overcome the poor leverage must also increase. Thus, in order to close the buckle, to a tight setting, the skier is faced with problems of decreased mechanical advantage and an increased force load which must be overcome. As can be appreciated, the buckle becomes very difficult to buckle as the desired tightness of the boot increases.
In order to tighten the ski boots to a relatively high degree, a skier may position the strap in a gap which is close to the pivot axis P. The skier will close the buckle with relative ease and then open the buckle and move the strap to a gap located a further distance from the pivot axis. This process is repeated until the desired tightness of the boot is reached. It should be understood that this process of tightening the boots is considered by some to be a difficult task since it requires the skier to bend over and push the buckle downwardly. The difficulty of buckling the boot is exacerbated because the buckling is typically done in a harsh environment such as at the top of a mountain after getting off the ski lift or tram. Moreover, each boot will typically include at least two buckles and often four or five buckles.
Once again referring to FIG. 1, the skier grasps the end portion of the buckle and pivots the buckle in a clockwise direction from the position shown in FIG. 1. When the buckle reaches a position wherein the strap 14 is in alignment or coincides with the pivot axis P, the buckle tends to snap or pivot quickly and with a great deal of force toward the boot. It is not unusual for a skier to catch his finger between the buckle and the boot. The force on the buckle may be such that the skier's fingers are bruised or cut.
It is an object of the present invention to provide a tool for opening and closing buckles on ski boots. More particularly, it is an object of the present invention to provide a tool which reduces the effort required by the skier to open and close the buckles on ski boots.